1. Field of the Invention
The present invention relates to control systems/methods for controlling the fueling of a fuel-controlled engine associated with an automated mechanical transmission system including an automated master friction clutch interposed between the engine and a transmission input shaft during vehicle launch operations.
2. Description of the Prior Art
Fully and partially automated mechanical transmission systems are well known in the prior art. See, for example, U.S. Pat. Nos. 4,361,060; 4,860,861; 4,648,290; 5,050,451; 5,272,939; 5,316,116 and 5,337,868, the disclosures of which are incorporated herein by reference. Such systems typically include a fuel-controlled engine, a fuel controller, a multiple-speed mechanical (i.e., jaw clutch-type) transmission, a transmission controller, a master friction clutch drivingly interposed between the engine and transmission and a microprocessor-based control unit (see U.S. Pat. No. 4,595,986, the disclosure of which is incorporated herein by reference) for receiving input signals and processing same according to logic rules to issue command output signals to system actuators.
It also is known to provide automated mechanical transmission systems with automatic clutch actuators and logic rules to control master clutch engagement during vehicle launch (also called "start-from-stop") operations. Examples of such vehicle launch controls may be seen by reference to U.S. Pat. Nos. 4,081,065; 4,638,898; 4,646,891; 4,714,144; 4,873,637; 4,874,070 and 5,316,116, the disclosures of which are incorporated herein by reference.
During engagement of the master clutch to launch a vehicle, it was known to control both the clutch actuator and the fuel actuator as functions of throttle position, engine speed, rate of change of engine speed and/or degree of clutch engagement to achieve a smooth, rapid clutch engagement while avoiding stalling and racing of the engine. To achieve this, the engine often was caused to be fueled in a gradually ramped-up manner to achieve an engine speed or engine flywheel torque determined by the control unit, regardless of the displacement of the throttle pedal. While these controls provide very acceptable vehicle launches under most conditions, the controls were not totally satisfactory, as response was somewhat sluggish, particularly when the vehicle was operating in a slow-speed creep or maneuvering mode or rapid acceleration of the vehicle is desired.